Kranjcar is an integral part of Portsmouth boss Harry Redknapp's plans

Portsmouth midfielder Niko Kranjcar is set to miss up to three months of the season after undergoing ankle surgery.

The 24-year-old ruptured ligaments on international duty for Croatia during their 3-2 win over Slovenia last week.

"He faces an estimated eight-to-12 weeks before being able to play first-team football again," read a statement on the club's website.

Kranjcar will now miss Croatia's crucial World Cup qualifier with England in Zagreb on 10 September.

The playmaker's absence is a huge blow for Portsmouth, who are currently bottom of the Premier League table having lost both of their matches this season.

Kranjcar was operated on by James Calder, a consultant orthopaedic surgeon specialist in foot and ankle surgery, on Wednesday morning.

A statement on the club's official website said: "The same surgeon operated on former Pompey player Pedro Mendes last season when he had a similar injury.

"Blues club doctor, Nigel Sellars, attended the operation along with the orthopaedic surgeon to the Croatia national team.

"The 24-year-old will wear a non-weight bearing case for the three weeks before beginning rehabilitation weeks."